Medicine for injection into a patient is commonly provided in a vial having a cap of rubber or plastic such as vial 16 of FIG. 1 having cap 15h. To remove the medicine from the vial, a medical practitioner inserts at hollow needle 14 which is attached to a syringe 17 through the cap 15 into the vial 16, presses a plunger 11 of the syringe 17 to pressurize the vial 16, and pulls back the plunger 11 until the desired dosage of medicine has been transferred from the vial to the syringe. The needle 14 used for removing the medicine from the vial is often not used to inject the medicine into the patient. For example, if the medicine is to be injected intravenously, the needle 14 for removing medicine from the vial is commonly discarded and the neck 12 of the syringe is attached to an intravenous system to administer the medicine.
This conventional procedure for transferring medication from a vial to a patient has the disadvantages that a medical practitioner is exposed to the danger of needle pricks, also that the practitioner frequently must perform the extra steps of unwrapping and attaching the needle to the neck of the syringe, pressurizing the vial before removing medicine, and removing the needle from the syringe and disposing of the needle before transferring the medicine to the patient.